Electric switch



G. SCHAFER ELECTRIC SWITCH Feb. 21, 1933.

Filed Dec. 3, 1930 in veizzor Patented Feb. '21, 1933 V UNITED STATESPATENT orrlcr.

. us'rav sexism, or armour, cumin? 7 mc-rmc 'swrrcn Applicatlon fledDecember 3, 1980, lerlal Io;

The known automatic switches for electrically heated implements sufierfrom the drawback that their sensitiveness to temperature is too slightand that dimensions are too 5 large for many urposes of use. The presentautomatic switc is distinguished by its high sensitiveness-j itoperates, for instance, at a difference of temperature of 3 C. Besides,it can be made so small that it can be inserted,

for instance, into the plug of an electric ticularly small and consistsof a comparatively wide, short and rigid part and of a comparativelynarrow, semi-circular tubular sprin which joins said first-mentionedpart axia y and is at its free end connected with a switch lever formedby a turnably arranged leaf spring, the free end of which acts upon acontact or contacts and co-operates with two other, but smaller leaf srings by which it is retained or checked in the one and the other of itstwo switchin positions (that in which the current is switc ed on andthat in which it is switched 05) until it is released by reason of itsincreasing bending through, whereafter the chain 'ng-over takes placeinstantaneousy sa1 by the interme iary of a lever, as is all more asfuiltv described hereinafter. y

invention is illustrated diagrammatically and'by way of eXampleonthe-accompan'ying drawing on which Figure 1 is a plan of a switchdesigned according to this invention, and Figure 2 is a front-viewthereof.

' The construction is as follows:

In the augularly bent part b of the base plate a is supported thecomparativel lar 'ri 'd container d from which exteng foifiii 45 axiallythe tublar spring d which, in contradistinction tothe known tubularsprings used in connection with electrically heatable implements, issemi-circularly shaped. Both partsdand d are. filled with a suitableliquid substance, for instance mercury. The container d is held inproper position by a nut ndin through becoming effective 490,781, and'inGermanynecember 8, 1889.

'w. The parts (i and d consist preferably at least partly of a goodconductor of heat, for instance copper, which is in intimate contact ofthe liquid substance enclosed in them; At-

the closed end of the tubular spring is an e e e u that is subjected tothe action of a helical sprin i, the other end of which is attached to ahoe h. .The eye 6 has an oblong slot 0' through which extends a bolt 9that is connected with one end of the leaf spring f. Near so the placeof connection of the eye c with the leaf spring f this latter passesthrough between two abutment members formed by edges or wedges c and Inbetween which said spring can turn or oscillate like a two-armed lever.To the free end of the leaf spring is attached a contact piece Z whichmay be ball-shaped and co-operates with a concave contact member m whichit has engaged in the position 7 shown in Fig. 1.

The contactpiece or member m is connected with a bracket 0 by means of ahelical spring" 11, and this bracket is fir secured-to the base late a,an insulatingpiate at "being provided between these two parts 3 is ascrew for connecting up one of the conductin wires, and g denotes apivot extending fort from the base plate and supporting a two-armedlever r, one arm of which is forked and provided with two pins 8 and t,the arrangement of which relatively to the leaf spring is such that thislatter passes through between them. The other end of said lever 1* whichis preferably rounded lies over the ends of two small leaf springs 10and c which are secured to the base plate' and extend obli uely from thesame to opposite directions w ich appears from Fig. 2 which also showsthat t ese springs cross one another.

The container d is closed at its lower end ,0

by means of a threaded plug p which serves for adjusting the switch byscrewing it in more or less so as to act thereby. upon the tubularspring. In the position ,of the ingthe switch rises, the'liquidsubstance enmo closedinthepartsdandd'willexpend whereby a pressure isexerted upon the tubu- 1211' spring so that its free end moves to theright, in consequence whereof the main portion of the leaf spring (belowthe abutment members a and k) w1ll be bent to the left.

More precisely, said leaf spring portion will be bent through to theleft, as its lower end is retained or checked by the small leaf sprlngea. In the same measure in which the temperaleaves the contact piece mso that the current is broken. The released endv of thespring f fliesforward with a'jerk so much that it gets behind the free end of-theother small leaf spring 4: by which it is then i checked and retained.If thereafter the temperature of the surroundin air decreases, as doesconsequently, also t e temperature of the liquid substance in the parts4! and d, the tubular spring will contract and the large leaf spring fwill now be bent through to the ri ht and will continue so until itcontacts wit h the pint. Then the lever 1' will again be turned, thesmall leaf springo will be depressed, the large leaf spring will againbe released and the contact members l and m. will again close thecircuit, as. will now be clear without further details of themovementsand' the operation of the parts concerned.

The other conducting wire can be. connected with any desired part of theswitch, especially the'base plate thereof, but if the current is not toflow through the switch said other wire can be connected with thecontact member Z'by means of a flexible spring or the like, in whichcase this contact member must be insulated from the spring f.

I claim:

L-An automatic switch for electrically heatable implements, comprising,in combination witha closed receptacle enclosing a .liquid substance andbeing composed of a rigid vessel andof a practically semicirculartubular spring, firmly connected, and

communicating at one of its ends, with said vessel, this latter having alarge diameter and being short in comparison with said tu-' bularspring; and vice versa, an elastic switching lever coupled with theother end of said tubular spring and being formed-of a leaf spring soarranged as to be adapted to be moved when the curvatureof said tubular'springis changed; a contact piece -at the free end of said leaf spring;another contact'piece opposite said first-mentioned one; two smallerleaf sprlngs so arranged relatively to the first-mentioned leaf springthat one thereof is adapted to check this latter spring in one of itsend positions, and. the other thereof is adapted to check the saidfirst-mentioned leaf-spring in the other of its end positions; and alever coupled with the first-mentioned leaf spring and adapted todepress the other two leaf springs alternately according to the positionof the first leaf spring as determined by the said tubular spring,substantially as set forth.

I 2. An automatic switch for use in connection with electrically.heatable implements, comprising, in combination, a closed receptacleenclosing a liquid substance filling the receptacle, and being composedof a rig d vessel and of a practically semi-circular tubular vesseldesigned'as a tubular spring and bein at one of its ends firmlyconnected with, an communicating with, said rigid vessel, this latterhaving alarge diameter and bei short in comparison with said spring, an7 viceversa; an elastic switching lever coupled with the other end ofsaid tubular spring and being constituted by a leaf-spring so arrangedas to be adapted to be moved when the curvature of the tubular springvaries; abutmentmembers located on the two sides of said leaf'spring andmaking it a two-armed lever;

a contact member at the free end of the leafand being inserted betweenit and said two 7 smaller leafsprings and being adapted to depress the nalternately, substantially and for the purpose set forth.

3. An automatic switch for use in connection with electrically heatabledevices, comprising, in combination, a closed receptacle with a liquidsubstance therein and composed of a comparatively short and wide, rigidve'ssel, and a circularly curved" elastic tube ;ex-

tending forth axially. from the rigid. vessel; and an elastic switchinglever coupled with the free endof the elastic tube and being formed by aleaf spring; a rigid two-armed lever and pins pro ecti ng forth from onearm thereof, said leaf spring passing through between said pins;:twosmaller leaf springs located below the other arm of said rigid leverand being so arranged with respect thereto as to be adapted .to bedepressed alternately by the same according to the position of thefirst-mentioned leaf spring as determined by the said tubular spring; a(ontact member attached to the free end of said first-mentionedleaf-spring, and another contact member arrangedopposite to said firstcontact member and being in contact with it at one of the two endpositionsof said leaf spring, as set forth.

In testimonywhereof I aflix'my signature. GUSTAV SGHAFER.--

